fio_plugin: add 1 io_queue_depth

Checked the code and found that our nvme perf example
added 1 io_queue_depth. Since if you set queue_depth=n,
the real entry is n - 1.

Change-Id: Ie204fc061b98e853e9b810eff21f79565c2ad8d0
Signed-off-by: Ziye Yang <optimistyzy@gmail.com>
Reviewed-on: https://review.gerrithub.io/367931
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

examples/nvme/fio_plugin/fio_plugin.c

@@ -92,6 +92,10 @@ static bool
 probe_cb(void *cb_ctx, const struct spdk_nvme_transport_id *trid,
 	 struct spdk_nvme_ctrlr_opts *opts)
 {
+	struct thread_data *td = (struct thread_data *)cb_ctx;
+
+	opts->io_queue_size = td->o.iodepth + 1;
+
 	return true;
 }